Clutch Delay Valve Delete/ PRL SS Clutch Line Install & Review

[gylmar814]

Good afternoon CivicX. Decided to do another write up on my latest modifications I thought I should share incase you haven't came across this very neat mod... I've done some research in the past and came up an article regarding the clutch delay valve (CDV) inside the slave cylinder and the positive outcome and results from deleting the valve. I've stumbled across several articles regarding the CDV delete anywhere from Bimmers to Honda's. Interestingly enough, I noticed @PRL Motorsports created a write up and did the CDV delete to their 10th gen Si as well... Now I personally haven't had any issues regarding clutch slippage during normal operation but when I'm WOT and shift in the upper RPM's its very noticeable the clutch slips briefly as I'm switching gears and causes a delay when shifting. I thought it was because of Rev Hang mixed with a weak OEM clutch (Although I still find the OEM Clutch to still be on the weaker end) and I just left it at that. I eventually found out the reason to the brief slippage is because there is a valve inside the slave cylinder the slows down the flow of the clutch fluid, therefore causing the clutch to slow down during engagement after shifting gears. Removing the valve allows the fluid to flow quicker, allowing the clutch to engage at a higher pressure. In other words, the clutch has a stronger bite and RPMs drop immediately when shifting gears like how a transmission is supposed to. Pretty much the point of having the CDV is for novice drivers who don't have experience driving manual gearboxes and really dumbs down the operation of the transmission.

To quote PRL:

"What does removing the CDV do? The engineers at Honda has been putting a CDV system on many of the recent platforms to reduce drivetrain shock. The CDV allows the clutch system to simulate "slip" in an attempt to save the transmission/drivetrain. However, for racers and enthusiasts looking for more of a raw driving experience in his or her car this can be annoying. Removing the CDV greatly improves clutch engagement which in turn improves 60fts and shift times. The other cool thing is this mod costs $0 aside from a new bottle of clutch fluid needed to bleed the clutch system. "

"The CDV is located in the slave cylinder which is attached on the front of the transmission. The slave sylinder can be removed by taking out the two 12mm bolts holding it on. Next you will need a 14mm and 10mm wrench to remove the clutch line from the slave cylinder. Now the slave cylinder assembly should be able to be completely removed."

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After deleting the CDV, it made a world of a difference! It honestly feels like I have a whole new clutch inside the car, almost making it feel like I have a Stage 1 clutch...That noticeable of a difference. The Clutch bites instantly with no slips during normal driving and aggressive high RPM operation MUCH better and RPM's drop between gears and shifting motion became much more fluid and natural. Best part is, it cost me $0. Only thing I bought was a bottle of brake fluid to top of the reservoir during the clutch bleeding process.

I figured it only made sense that since I was taking apart the slave cylinder and having to bleed the clutch afterwards, I should buy PRL's Stainless Steel Braided Clutch line in the process and kill 2 birds with 1 stone. With the combination of the CDV Delete and the PRL SS line I have nothing but good to say about this mod. You can tell the difference even with the foot. The clutch feels more stronger and firm when pressing & depressing the pedal, how it should have felt out of the factory.

Here is the link to PRL's thread for more information: https://www.civicx.com/threads/10th-gen-civic-1-5t-clutch-delay-valve-removal.13105/

Link to PRL's Stainless Steel Clutch line, only cost about $42 after shipping. : http://prlmotorsports.com/2016civic15tstainlesssteelbraidedclutchline.aspx#.WpdJT-jwaUk

Here are some pictures with captions for reference purposes, enjoy!

First and Foremost, I highly recommend a set of scribe/picking tools like this one. There is a "C" locking ring that locks a metal cap that is a bitch and a half to take off. Luckily for me, it only took about 10-15 minutes to wiggle it out. Once you take it off, you can use a set of needle nose pliers preferably with grip teeth and pull off the metal cap. Once you take it off you will see the white CDV valve in the inside (See pics below). You can use the same tools you used to take off the "C" locking ring to take off the valve and then throw the valve away!

Here is where the Slave Cylinder is. Its attached in front of the transmission. All it takes is a 12mm socket with a ratchet to remove the slave cylinder off the tranny and a 10mm wrench to remove the clutch line off the slave cylinder.

How it looks after removal of the SC. I put a ziploc bag so it can catch the clutch fluid coming off the line.

This is the Slave Cylinder out of the vehicle. On the left side of the SC is where the metal cap and locking ring is located. I completly forgot to take a picture of how it looks but its self explanatory once you take off the SC and see it for yourself! This is also when you use the picking tools and pick out the locking ring.

This is how it looks once you take off the C locking ring and the metal cap on the other end of the slave cylinder. This is the Clutch Delay Valve inside the SC

This is the C locking ring and the Metal cap that needs to be removed. This is to be installed back exactly how it was, once you remove the clutch delay valve inside.

This is the Clutch Delay Valve the needs to be removed and thrown away.

This is how the inside of the SC looks once you take off the Clutch Delay Valve

PRL Stainless Steel Clutch line Installed

Zoomed in shot of the Clutch Line

 

[maaaaackle]

So, as someone who never races and just loves driving stick, would you recommend this?

The clutch on my hatch is really light...it bothers me a little bit.

 

[gylmar814]

So, as someone who never races and just loves driving stick, would you recommend this?

The clutch on my hatch is really light...it bothers me a little bit.

I don't race either. Yes I would recommend. In the long run you are making the clutch last longer preventing the CDV from letting it slip when you shift gears. One of the reasons of having the CDV is so it reduces the drivetrain shock. But if you know how to drive manual good, that shouldn't be an issue.

After doing both the delete and the SS line.. the clutch noticeably feels more firm.

 

[Scarlet]

I don't race either. Yes I would recommend. In the long run you are making the clutch last longer preventing the CDV from letting it slip when you shift gears. One of the reasons of having the CDV is so it reduces the drivetrain shock. But if you know how to drive manual good, that shouldn't be an issue.

After doing both the delete and the SS line.. the clutch noticeably feels more firm.

This is a false statement, almost opposite of what you're stating.. Also, the firmness is likely due to the upgraded SS line alone, can't flex under pressure like the rubber line does. Not trying to be rude or rain on your parade, just want our community to be informed correctly.

 

[gylmar814]

W

This is a false statement, almost opposite of what you're stating.. Also, the firmness is likely due to the upgraded SS line alone, can't flex under pressure like the rubber line does. Not trying to be rude or rain on your parade, just want our community to be informed correctly.

What is it that you are referring to is false compared to what PRL mentioned? Not sure if I'm understanding correctly

Also , yes I understand the SS line alone is probably the cause for the firmness but not gonna say it was that just alone. Maybe the because of the CDV delete, now there is no valve in the way for the fluid pressure to the slave cylinder. Which would cause the fork to have a stronger engagement so the clutch bites harder.

That's why in my post I mentioned the "combination" of both the SS line and the CDV delete.

 

[Axatax]

This is a false statement, almost opposite of what you're stating.. Also, the firmness is likely due to the upgraded SS line alone, can't flex under pressure like the rubber line does. Not trying to be rude or rain on your parade, just want our community to be informed correctly.

It looks like he's concurring with the thread linked at the bottom of your post, but you're only quoting a portion of his explanation.

What I took away after reading his entire thread is this: It can cause more wear and tear, but if a person is experienced driving stick, any excess wear will be minimal but the clutch feel will be improved.

That's what I got of both threads anyhow. They seem to be in agreement to me.

 

[gylmar814]

It looks like he's concurring with the thread linked at the bottom of your post, but you're only quoting a portion of his explanation.

What I took away after reading his entire thread is this: It can cause more wear and tear, but if a person is experienced driving stick, any excess wear will be minimal but the clutch feel will be improved.

That's what I got of both threads anyhow. They seem to be in agreement to me.

Exactly what you took in what I wrote is what I meant. What I mentioned about the CDV delete is the same thing PRL said. I just worded it differently if that's the confusion. I said the point of the CDV is to reduce drive train shock. However if you decide to delete it, you can minimize that shock or it shouldn't be an issue if you have experience driving manual. Just like PRL mentioned as well the average Joe should be fine

 

[Scarlet]

I was mostly referring to your statement that removing the valve would increase clutch life, etc. Removing that valve will cause more wear on the clutch and all drivetrain components.

 

[Axatax]

I was mostly referring to your statement that removing the valve would increase clutch life, etc. Removing that valve will cause more wear on the clutch and all drivetrain components.

But if that valve is intentionally introducing slip that might not be so for an experienced driver.

 

[gylmar814]

I was mostly referring to your statement that removing the valve would increase clutch life, etc. Removing that valve will cause more wear on the clutch and all drivetrain components.

If the purpose of the clutch delay valve is to delay the clutch engagement, thereore causing the the clutch to slip upon shifting gears so it reduces shock especially at higher rpms... I don't see how deleting the valve wears the clutch faster. As for everything else in the drivestrain, yes I agree. But like I said, depending how well you drive manual or not.. this can or cannot be an issue in the long run

 

[Axatax]

The NA 2.0 and 1.5T both have the same part # for the slave cylinders so it probably has it too.

 

[gylmar814]

The NA 2.0 and 1.5T both have the same part # for the slave cylinders so it probably has it too.

Yeah I'm sure it does.

 

[silversurfer22]

Great write up. I do hate how light the clutch is. Will give this a try with the ss clutch line.

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